/**
 * 从输入中获取operator或者operand
 */

#include <stdio.h>
#include <ctype.h>
#include "calc.h"

int getop(char s[]) {
    int i, c;
    
    while ((s[0] = c = getch()) == ' ' || c == '\t') ;
    s[1] = '\0';
    if (!isdigit(c) && c != '.')
        return c;
    i = 0;
    if (isdigit(c))
        while (isdigit(s[++i] = c = getch())) ;
    if (c == '.')
        while (isdigit(s[++i] = c = getch())) ;
    s[i] = '\0';
    if (c != EOF)
        ungetch(c);

    return NUMBER;
}
